Heat sink



FIG. 1 is a top/left side perspective view of the heat sink.

FIG. 2 is a bottom/right side perspective view of the heat sink.

FIG. 3 is a front view of the heat sink.

FIG. 4 is a rear view of the heat sink.

FIG. 5 is a right side view of the heat sink.

FIG. 6 is a left side view of the heat sink.

FIG. 7 is a top view of the heat sink; and,

FIG. 8 is a bottom view of the heat sink.

The broken lines shown in FIGS. 1-8 represent portions of the heat sink design that form no part of the claim. 

CLAIM The ornamental design for a heat sink, as shown and described. 